While many areas of the ocean are rich in other nutrients, they often lack iron—a critical element for marine life. Dissolved iron in seawater can originate from three main sources: dust from the atmosphere, sediment dissolution along continental margins, and fluids from hydrothermal vents. (Jack Cook,Woods Hole Oceanographic Institution )

February 23, 2015Full resolution (750 × 563)

While many areas of the ocean are rich in other nutrients, they often lack iron—a critical element for marine life. Dissolved iron in seawater can originate from three main sources: dust from the atmosphere, sediment dissolution along continental margins, and fluids from hydrothermal vents. (Jack Cook,Woods Hole Oceanographic Institution )